Error instead of termination

[Michael-E-Rose]

If input criteria are not of the expected form (such as that the input is not a numpy array), the object throws a message and then terminates the execution. Neither is standard or desirable. Instead, the object should throw an exception (probably AttributeError) and nothing else.

[open-risk]

type and value checking has been streamlined. more in-depth testing will likely come in the future (after a new round of index additions and a likely api redesign)